Stamping mass for metallurgical furnaces

ABSTRACT

A refractory stamping mass wherein essentially sand or dolomite and carbon from coal or coke and a binding agent is used for metallurgical furnaces, the improvement which consists in the addition of a phenoplast precondensate.

0 United States Patent 1 [111 3,717,602

Koch et a1. Feb. 20, 1973 [54] STAMPING MASS FOR METALLURGICAL FURNACES [56] References Cited Inventors: Karl Heinz Koch, Dortmund- Benninghofen; Paul Koch, Letmathe-Untergrune; Walter Loorz, 2,988,525 6/ 1961 Clem ..l06/38.8 Dortmund-Lucklenberg; Hans 3,418,402 12/1968 Grissom .....106/38.8 Schoppa Dortmund, all of Germany 3,057,026 10/1962 Blaies ..260/38 3,607,809 9/1971 Elby ..260/28 [73] Asslgneez DIdIer-Werke A.G., wlesbaden,

Germany Primary Examiner-Morris Liebman [22] Filed: Nov. 13, 1970 Assistant Examiner-P. R. Mich! [211 pp No: 89,481 Attorney-Wenderoth, Lind & Ponack Related US. Application Data [57] ABSTRACT [63] Continuation of Ser. No. 712,389, March 12, 1968, A refractory stamping mass wherein essentially s'and abandoned. -or dolomite and carbon from coal or coke and a binding agent is used for metallurgical furnaces, the im- [52] US. Cl. ..260/28, 106/388, 260/38, movement which consists in the addition of a 260/DIG- 40 phenoplast precondensate. [5 1] Int. Cl. ..C08g 51/52 [58] Field of Search ..l06/38.8; 260/38, 28 1 Claim, No Drawings STAMPING MASS FOR METALLURGICAL FURNACES This application is a continuation of Ser. No. 712,389, filed Mar. 12, 1968, now abandoned.

The invention relates to a refractory stamping mass consisting essentially of sand or dolomit and/or carbon in the form of coal or coke as well as a binding agent for metallurgical furnaces.

With such stamping masses metallurgical furnaces are prepared. Besides, the stamping mass serves for the relining of refractory metallurgical furnaces and for the closing of tap holes.

For the lining of metallurgical furnaces the hardening of the refractory mass is accomplished by the heating of the furnace. During the relining of the refractory lining and during the closing of tap holes the hardening is accomplished by the heat inherent within the furnace. Especially during the relining of refractory linings and during the closing of tap holes a short time of hardening of the stamping mass used for the relining or closing of the tap holes is desirable.

Known stamping masses require hardening times within the order of magnitude of 1 hour. This period of time will have to be necessarily passed after the closing of the tap hole if one does not want to risk that the furnace breaks through. If spots to be relined are concerned, in such case a premature operation of the furnace results in an immediate undesired washing out of the applied stamping mass.

An object of the present invention is to solve the above problem by having the refractory stamping mass for metallurgical furnaces consist essentially of sand or dolomit and/or carbon in the form of coal or coke with a binding agent added consisting of a phenoplast condensate such as resoles and novolaks whereby the stamping mass is mixed in the relation of two to four percent of the base material.

Such masses suffice in a sufficiently hardened condition the requirements in regard to temperature stability as well as mechanical resistance and display in regard to known stamping masses essentially shorter hardening times. The shortened hardening time is especially advantageous in regard to metallurgical furnaces being in operation, since the stopping time after the repair of a furnace or after the tapping can be correspondingly shortened which results in a higher melting capacity in relation to the furnace. Besides, especially when using the stamping mass according to the present invention for the tapping of furnaces labor can be reduced, since the tap hole stamping masses hitherto left for 1 hour and longer after the closing of the tapping at the tap hole can be now removed after about 10 minutes, so that a longer time is available for the preparation of the next tapping.

For keeping a supply as is desirable for a continuous operation, the use of novolaks is preferred to the one of resoles, since resoles have the tendency to form lumps and therefore immediately before the addition to the base mass have to be transferred by grinding to the necessary pulverized condition for a satisfactory blending, while ground novolaks maintains its pulverized condition also for longer periods of time.

Commercial novolaks have a percentage of 5 to 15 percent of hexamethylene tetramine.

For stamping masses which have tar as a binding agent, according to a further embodiment of the present invention the addition of novolaks with an 1ncreased percentage of hexamethylene tetramine is suggested, preferably with a percentage of 15 to 50 percent. Because of the surplus hexamethylene tetramine the hydroxyl containing cyclic groups of hydrocarbons of the tar are participating in the hardening, whereby a desirable increase in the temperature stability and the mechanical resistance of the hardened stamping masses is obtained. The following is an example of the present invention: The base mass, namely fine sand 15% crude tar l00% was mixed in a mixing drum with 3 percent pulverized novolaks (consisting of 30 percent of hexamethylene tetramine) in relation to the base mass.

With a mass sufficient for several tappings on a 9 meter blast furnace a tap hole was closed in successive tappings. 10 minutes after the closing of the tap hole the hardening of the applied mass was accomplished and the tap hole stamping machine could be removed.

What is claimed is:

l. A stamping mass for metallurgical furnaces, consisting essentially of 85 percent fine sand, and 15 percent crude tar as the base material and 3 percent of a novolak'resin consisting of 30 percent hexamethylene. tetramine, wherein the percentage of the novolak is based on the total amount of base material.

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